Hey guys, I was wondering if I could get some help diagnosing a problem before I take it in the mechanic.
The problem:
A sudden loss of power, typically at mid-to-high RPM's, under load. The problem first happens quite faintly, barely noticeable then progressively gets worse over the next few minutes. Under low rpm's/light load, it doesn't seem to happen very often.
The CEL does come on after a few minutes of this. I've got a code scanner. Here's what it says:
P0300 - Random/Multiple Cylinder Misfire detected.
Well, duh.
Background
It's a 2002 Protege5, 85000 km on it. I got it used 3 months ago from a Kia dealer. No service records from previous owner. I had no problems with it the first 3 months.
About 3 weeks ago I took it on a road trip, including 5-6 hours of driving on dirt roads. The car handled it no problem, but on the way back this problem first appeared. My initial diagnosis was a clogged air filter, and sure enough, when I pulled it out it was black as night. I banged it out against my shoe, then bought a new one 30 km later. Made it home without the problem reappearing.
Then it started happening again a few days ago. The problem is obviously not entirely the air filters fault.
Ideas:
Spark plugs? Wires? Distributor? Fuel Injectors? Fuel Pump? Something else entirely?
I don't have a garage or driveway to do any wrenching myself in, but if you think it's a straightforward problem I can go over to my parents place and do it there.
Thanks for your help and ideas in advance.
The problem:
A sudden loss of power, typically at mid-to-high RPM's, under load. The problem first happens quite faintly, barely noticeable then progressively gets worse over the next few minutes. Under low rpm's/light load, it doesn't seem to happen very often.
The CEL does come on after a few minutes of this. I've got a code scanner. Here's what it says:
P0300 - Random/Multiple Cylinder Misfire detected.
Well, duh.
Background
It's a 2002 Protege5, 85000 km on it. I got it used 3 months ago from a Kia dealer. No service records from previous owner. I had no problems with it the first 3 months.
About 3 weeks ago I took it on a road trip, including 5-6 hours of driving on dirt roads. The car handled it no problem, but on the way back this problem first appeared. My initial diagnosis was a clogged air filter, and sure enough, when I pulled it out it was black as night. I banged it out against my shoe, then bought a new one 30 km later. Made it home without the problem reappearing.
Then it started happening again a few days ago. The problem is obviously not entirely the air filters fault.
Ideas:
Spark plugs? Wires? Distributor? Fuel Injectors? Fuel Pump? Something else entirely?
I don't have a garage or driveway to do any wrenching myself in, but if you think it's a straightforward problem I can go over to my parents place and do it there.
Thanks for your help and ideas in advance.